HDU 2433 Travel

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define INF 0x3f3f3f3f
15 using namespace std;
16 const int maxn = 110;
17 int sum[maxn],d[maxn],num[maxn][maxn],n,m;
18 bool arc[maxn][maxn],used[maxn][maxn][maxn],in[maxn];
19 int q[maxn*maxn],head,tail,e[3002][2];
20 int spfa(int s,bool is){
21     for(int i = 1; i <= n; i++){
22         in[i] = false;
23         d[i] = INF;
24     }
25     head = tail = d[s] = 0;
26     in[s] = true;
27     q[tail++] = s;
28     while(head < tail){
29         int u = q[head++];
30         in[u] = false;
31         for(int i = 1; i <= n; i++){
32             if(arc[u][i] && d[i] > d[u]+1){
33                 d[i] = d[u]+1;
34                 if(!in[i]){
35                     in[i] = true;
36                     q[tail++] = i;
37                     if(is) used[s][u][i] = used[s][i][u] = true;
38                 }
39             }
40         }
41     }
42     int ans = 0;
43     for(int i = 1; i <= n; i++){
44         if(d[i] == INF){ans = INF;break;}
45         ans += d[i];
46     }
47     return ans;
48 }
49 int main(){
50     int i,j,u,v,ans;
51     while(~scanf("%d %d",&n,&m)){
52         memset(arc,false,sizeof(arc));
53         memset(used,false,sizeof(used));
54         memset(num,0,sizeof(num));
55         memset(sum,0,sizeof(sum));
56         for(i = 0; i < m; i++){
57             scanf("%d %d",&u,&v);
58             arc[u][v] = arc[v][u] = true;
59             num[u][v]++;
60             num[v][u]++;
61             e[i][0] = u;
62             e[i][1] = v;
63         }
64         ans = 0;
65         for(i = 1; i <= n; i++){
66             sum[i] = spfa(i,true);
67             if(sum[i] == INF){ans = INF;break;}
68             ans += sum[i];
69         }
70         int tmp = 0;
71         for(i = 0; i < m; i++){
72             u = e[i][0];
73             v = e[i][1];
74             int ans2 = ans;
75             if(ans == INF) puts("INF");
76             else if(num[u][v] > 1) printf("%d\n",ans);
77             else{
78                 arc[u][v] = arc[v][u] = false;
79                 for(j = 1; j <= n; j++){
80                     if(used[j][u][v]){
81                         tmp = spfa(j,false);
82                         if(tmp == INF) break;
83                         ans2 += tmp - sum[j];
84                     }
85                 }
86                 if(tmp == INF) puts("INF");
87                 else printf("%d\n",ans2);
88                 arc[u][v] = arc[v][u] = true;
89             }
90         }
91     }
92     return 0;
93 }